docs: def decrease_posts_count_after_post_deletion(sender, instance, **kwargs):
      """ Decreases the member's post count after a post deletion.
  
      This receiver handles the deletion of a forum post: the posts count related to the post's
      author is decreased.
      """
      if not instance.approved:
          # If a post has not been approved, it has not been counted.
          # So do not decrement count
          return
  
      try:
          assert instance.poster_id is not None
          poster = User.objects.get(pk=instance.poster_id)
      except AssertionError:
          # An anonymous post is considered. No profile can be updated in
          # that case.
          return
      except ObjectDoesNotExist:  # pragma: no cover
          # This can happen if a User instance is deleted. In that case the
          # User instance is not available and the receiver should return.
          return
  
      profile, dummy = ForumProfile.objects.get_or_create(user=poster)
      if profile.posts_count:
          profile.posts_count = F('posts_count') - 1
          profile.save()